By contrast, other types of EU law (such as EU directives) have to be given effect in the UK through national laws. This has frequently been done using section 2(2) of the ECA, which provides ministers, including in the devolved administrations, with powers to make secondary legislation to implement EU obligations. Once the ECA has been repealed, all of the secondary legislation made under it would fall away. As this would also leave a significant gap in the statute book, the Bill will also preserve the laws we have made in the UK to implement our EU obligations.

High

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/604516/Great_repeal_bill_white_paper_accessible.pdf

Chapter 2, Paragraph 2.5